The present invention relates to an angle adjustable joint for use in furnitures which can be conveniently adjusted from one position to another and firmly retained at any of a variety of angles.
In furnitures, a joint may be fastened between two parts so that they can be rotated with one against the other. FIG. 1 illustrates a prior art joint used in furnitures. This joint is consisted of a locating member, a driven member, a brake member, a torsional spring, and a return plate. The driven member is pivoted to the locating member. The brake member is supported on the torsional spring and rotated by the driven member to engage into either pitch on a series of teeth on each of two parallel ratchet plates on one end of the locating member. Rotating the driven member on the locating member causes the brake member to change its engagement with the teeth on the locating plate from one to another permitting the driven member to be positioned at either of a plurality of angles relative to the locating member (see FIGS. 1A, 1B and 1C). In this structure of joint, each ratchet plate of the locating member has only four teeth for adjusting the angular position of the driven member relative to the locating member, and therefore the joint can only be adjusted and positioned at either of five angles including horizontal and vertical angles. The pitch between each two adjacent angles is about 22 angle. This wide pitch can not satisfy all consumers. However, simply increasing the number of teeth will reduce the bearing strength of each tooth, and the teeth may be damaged easily. Furthermore, increasing the number of teeth will also increase the tooling charge. If to reinforce the bearing strength of the teeth by increasing the thickness of the ratchet plates, the manufacturing cost of the joint will be greatly increased.